This study will investigate the links between participation in a sustained, federally-funded early childhood intervention and well-being up to age 35 for a large inner-city cohort of children in the Chicago Longitudinal Study (CLS). The central purpose is to determine if participation in the Child-Parent Center (CPC) Early Education Program for different lengths of time is associated with better health and well-being 26 to 30 years later. Consistent with the high intensity and comprehensiveness of services, a comprehensive set of measures will be investigated to early midlife for participants and their families. These include economic self-sufficiency, career success, and occupational status; physical health and health behaviors; mental health, psychological well-being, and quality of life; educational attainment; social behavior and criminality; and family well-being including parenting and schooling effects on the children of participants. Among the primary questions are the following: (a) Is participation in the CPC program beginning in preschool associated with greater well-being in multiple domains in the fourth decade of life? (b) Does participation in the CPC extended intervention from ages 3 to 9 contribute to adult well-being above and beyond less extensive intervention?, (c) What are the mechanisms through which intervention affects well-being and for different subgroups?, and (d) What are the comparative economic benefits of intervention? The long-term goals include to increase knowledge about the long-run and complex effects of early intervention across a wide range of outcomes and to translate research finding and principles for the promotion of sustained programs and services. The study sample includes 911 program (92% of original sample) and 492 matched comparison group (90% of original sample) participants who enrolled for up to 6 years of intervention beginning at age 3. 93% of the sample are African American. Participants have been followed since birth and extensive data on child, family, and school experiences have been collected from many sources. In the next five years, we will collect, obtain, and analyze a comprehensive set of new data from employment and income, educational, justice system, public aid and health, social-service records, and from the age-31/32 interview of participants; analyze existing data from multiple sources and time periods; and will continue to track life-course development. This study is not only the most extensive of a public early intervention but an efficient use of resources for advancing knowledge on life course and intergenerational impacts. Findings will provide among the best available knowledge of the effects and cost-effectiveness of an established school-based early childhood intervention.